UPDATE 1-EV maker Rivian expects wider operating loss for year

(Adds details on adjusted operating loss forecast, shares)

Aug 11 (Reuters) - Electric-vehicle maker Rivian Automotive Inc on Thursday forecast a wider operating loss for the year, sending its shares down nearly 2% in extended trading.

Rivian said it now expects to post an adjusted loss before interest, taxes, depreciation and amortization of $5.45 billion, compared with $4.75 billion previously.

The company, however, beat quarterly revenue estimates as a ramp-up in production helped it deliver more SUVs, pickup trucks and vans.

The Irvine, California-based company has in recent months started overcoming the supply chain issues and semiconductor shortages that have curtailed its ability to meet soaring demand for electric vehicles.

Rivian reiterated its annual production forecast of 25,000 units and said it expects to add a second shift for vehicle assembly at its Normal, Illinois plant towards the end of the third quarter.

In the second quarter ended June 30, the EV maker delivered 4,467 vehicles, up from 1,227 units in the previous three months.

The company said it has received about 98,000 pre-orders for its R1S SUV and R1T pickup truck.

Revenue was $364 million in the second quarter, compared with the $337.5 million expected by analysts, according to IBES data from Refinitiv.

Net loss widened to $1.71 billion, from $580 million a year earlier. (Reporting by Akash Sriram in Bengaluru and Paul Lienert in Detroit; Editing by Aditya Soni)